How to retrieve Facebook response using Facebook iOS SDK - ios

Question

I am using the Facebook iOS SDK for iPhone. I initialize the Facebook instance
facebook = [[Facebook alloc] initWithAppId:kAppId];
And then I do login:
[facebook authorize:permissions delegate:self];
After I logged in to Facebook I am doing the following to get the user profile information:
[facebook requestWithGraphPath:#"me" andDelegate:self];
NSMutableData *response = [fbRequest responseText];
unsigned char *firstBuffer = [response mutableBytes];
NSLog(#"Got Facebook Profile: : \"%s\"\n", (char *)firstBuffer);
But I get the following on my console:
Got Facebook Profile: "(null)"
What am I doing wrong, also I believe that Facebook response is a json string and I am looking to get a hold of that json string.

Answer 1

I thought may be I should make it a wiki and tell the people how I am doing it. because lot of people are facing similar problem.
The first thing that I did was.
In Facebook.m class I added the following statement in the following method
(void)authorizeWithFBAppAuth:(BOOL)tryFBAppAuth
safariAuth:(BOOL)trySafariAuth
trySafariAuth = NO;
This prevents a safari page to get open for the facebook login, but it pops up a screen in app itself. Then i created a helper class for Facebook, the header file code is here.
#import <UIKit/UIKit.h>
#import "FBConnect.h"
#interface FaceBookHelper : UIViewController
<FBRequestDelegate,
FBDialogDelegate,
FBSessionDelegate>{
Facebook *facebook;
NSArray *permissions;
}
#property(readonly) Facebook *facebook;
- (void)login;
-(void)getUserInfo:(id)sender;
- (void)getUserFriendList:(id)sender;
-(void)postToFriendsWall;
The .m file.
static NSString* kAppId = #"xxx";
#define ACCESS_TOKEN_KEY #"fb_access_token"
#define EXPIRATION_DATE_KEY #"fb_expiration_date"
#implementation FaceBookHelper
#synthesize facebook;
//////////////////////////////////////////////////////////////////////////////////////////////////
// UIViewController
/**
* initialization
*/
- (id)init {
if (self = [super init]) {
facebook = [[Facebook alloc] initWithAppId:kAppId];
facebook.sessionDelegate = self;
permissions = [[NSArray arrayWithObjects:
#"email", #"read_stream", #"user_birthday",
#"user_about_me", #"publish_stream", #"offline_access", nil] retain];
[self login];
}
return self;
}
///////////////////////////////////////////////////////////////////////////////////////////////////
// NSObject
- (void)dealloc {
[facebook release];
[permissions release];
[super dealloc];
}
///////////////////////////////////////////////////////////////////////////////////////////////////
// private
/**
* Login.
*/
- (void)login {
// only authorize if the access token isn't valid
// if it *is* valid, no need to authenticate. just move on
if (![facebook isSessionValid]) {
[facebook authorize:permissions delegate:self];
}
}
/**
* This is the place only where you will get the hold on the accessToken
*
**/
- (void)fbDidLogin {
NSLog(#"Did Log In");
NSLog(#"Access Token is %#", facebook.accessToken );
NSLog(#"Expiration Date is %#", facebook.expirationDate );
// Store the value in the NSUserDefaults
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:facebook.accessToken forKey:ACCESS_TOKEN_KEY];
[defaults setObject:facebook.expirationDate forKey:EXPIRATION_DATE_KEY];
[defaults synchronize];
// This is the best place to login because here we know that user has already logged in
[self getUserInfo:self];
//[self getUserFriendList:self];
//[self postToFriendsWall];
}
- (void)fbDidNotLogin:(BOOL)cancelled {
NSLog(#"Failed to log in");
}
- (void)getUserInfo:(id)sender {
[facebook requestWithGraphPath:#"me" andDelegate:self];
}
- (void)getUserFriendList:(id)sender {
[facebook requestWithGraphPath:#"me/friends" andDelegate:self];
}
////////////////////////////////////////////////////////////////////////////////
// FBRequestDelegate
/**
* Called when the Facebook API request has returned a response. This callback
* gives you access to the raw response. It's called before
* (void)request:(FBRequest *)request didLoad:(id)result,
* which is passed the parsed response object.
*/
- (void)request:(FBRequest *)request didReceiveResponse:(NSURLResponse *)response {
NSLog(#"Inside didReceiveResponse: received response");
//NSLog(#"Status Code #", [response statusCode]);
NSLog(#"URL #", [response URL]);
}
/**
* Called when a request returns and its response has been parsed into
* an object. The resulting object may be a dictionary, an array, a string,
* or a number, depending on the format of the API response. If you need access
* to the raw response, use:
*
* (void)request:(FBRequest *)request
* didReceiveResponse:(NSURLResponse *)response
*/
- (void)request:(FBRequest *)request didLoad:(id)result {
NSLog(#"Inside didLoad");
if ([result isKindOfClass:[NSArray class]]) {
result = [result objectAtIndex:0];
}
// When we ask for user infor this will happen.
if ([result isKindOfClass:[NSDictionary class]]){
//NSDictionary *hash = result;
NSLog(#"Birthday: %#", [result objectForKey:#"birthday"]);
NSLog(#"Name: %#", [result objectForKey:#"name"]);
}
if ([result isKindOfClass:[NSData class]])
{
NSLog(#"Profile Picture");
//[profilePicture release];
//profilePicture = [[UIImage alloc] initWithData: result];
}
NSLog(#"request returns %#",result);
//if ([result objectForKey:#"owner"]) {}
};
/**
* Called when an error prevents the Facebook API request from completing
* successfully.
*/
- (void)request:(FBRequest *)request didFailWithError:(NSError *)error {
//[self.label setText:[error localizedDescription]];
};
////////////////////////////////////////////////////////////////////////////////
// FBDialogDelegate
/**
* Called when a UIServer Dialog successfully return.
*/
- (void)dialogDidComplete:(FBDialog *)dialog {
//[self.label setText:#"publish successfully"];
}
#end

Answer 2

Thanks for this hint Yogesh!
In facebook.m you can also set the safariAuth param in the authorize method.
- (void)authorize:(NSArray *)permissions
delegate:(id<FBSessionDelegate>)delegate {
...
[self authorizeWithFBAppAuth:YES safariAuth:NO];
}